Abhi to the rescue!

Countless animals right from mighty elephants to tiny frogs lose their lives to reckless, speeding vehicles each year in India. Photo: Sanjay Gubbi.

Abhi looks out the window from the backseat. He and his parents are on their way to his grandmother’s house in the village. They’re driving through a road that runs along a forest. He daydreams about the village, the emerald trees that whisper sha-sha-sha in the wind, the murmur of the river, the fireflies that float around the house like sparks of crackling wood in a bonfire.

He sees a large brown bag with dark liquid oozing out of it on the road in the distance. As they move closer to it, he sees it move a little. It’s definitely not a bag, he thinks.

He shouts out a warning, and his father stops the car. He runs out towards the thing on the road, his mother following close behind.

It’s a snake! And it’s badly hurt. Its tail is covered in blood and it lies motionless near criss-cross imprints of tyres. Abhi is careful; he doesn’t get too close.

“We must do something,” Abhi says. “We must try and save the poor snake!”

He looks around worriedly. Ah! He sees a signboard with a picture of a leopard on it. “CALL THIS NUMBER IF YOU SEE AN INJURED ANIMAL” it says in big, bold letters. Seized with hope, he takes his mother’s phone and dials the number.

“Hello, there’s… there’s a snake badly hurt on the road! I don’t know if it’s alive or… Please can you save it?” he pleads. His mother takes the phone and tells the lady the location and the number of their car so that they can easily find them. The voice on the phone promises to be there in ten minutes.

They wait in the car. Abhi admires the irregular patchwork of brown hues on the snake’s back. It looks as though a piece of paper which was once crumpled and torn was now put together like a jigsaw puzzle. Earlier, he was certain he had seen it move, but he isn’t too sure anymore.

Soon enough, a khaki-coloured gypsy pulls over right next to them. Three people get off, and two men start examining the snake. Ira, a young researcher, walks towards them and starts talking to his parents. Abhi watches as they carefully lift the snake and place it inside a wooden box.

“Its eyes are open… that surely means its alive right?” asks Abhi, his eyebrows crumpled with concern.

“Snakes don’t have eyelids, so their eyes are always open. You did the right thing, Abhi. We can’t thank you enough. We will do everything we can. Dr. Mishra here is a very skilled veterinarian and he has handled many injured pythons before.”

Wow! A python, thinks Abhi, and looks tenderly at the beautiful, wounded creature, now curled inside the box. And just as they are about to pick it up, he sees the snake tuck its head in its coils.

“It’s alive!” Abhi squeals. “It’s alive Ma, I saw it move! I saw it turn its head!”

(Continued next week…)

•Highways that pass through forests often prove to be fatal to wildlife.

•Hundreds of wild animals are killed by speeding vehicles each year in India, and they include elephants, tigers, sloth bears, snakes, frogs, and many others.

•Between July 2009 and June 2014, as many as 23 leopards were killed in road accidents in Karnataka alone.

• Reptiles and amphibians are known to be the most affected by vehicular traffic, but there is very little information available on such accidents.

•It’s very important to follow the speed limit and to be extra cautious and alert while driving through ecologically important areas.

Source: TH

#17, #2015, #august

Stones pelted at a chemical factory in Nellore

Some sections of local leaders and residents pelted stones at a chemical factory located near Chandrapadia village in Vinjamur mandal limits here on Sunday night which caused damage to furniture and window panes.

On information provided by the management, the Vinjamur police launched action and reportedly took into custody 10 persons in connection with the alleged vandalism.

Sources said that there has been a long-standing agitation by some local leaders against the Nutra Specialties factory. Their contention was that the chemical effluents from the factory were polluting their village and surrounding areas and the situation would aggravate in the near future.

However, the factory ruled out any harm from their side to the environment and asserted that all steps had been taken in this regard. The issue was discussed at the district officials’ level but the differences continued.

Source: TH

#17, #2015, #august

Sodium cyanide traces found in waters near site of China blasts

Indication that it has spread to the sea, even as experts raced against time to clear the area of toxic chemicals stored at the ravaged warehouse

Smoke rises from damaged container boxes near the site of an explosion at a warehouse in northeastern China's Tianjin municipality on Monday. Minute traces of cyanide have been detected in waters near the Tianjin port, the State Oceanic Administration said acknowledging that it was spreading into the waters of the port which is on the western shore of the Bohai Bay.

Minute traces of sodium cyanide have been found in waters near China’s Tianjin port indicating that it has spread to the sea, even as experts raced against time to clear the area of toxic chemicals stored at a warehouse ravaged by blasts that killed at least 114 people.

Minute traces of cyanide have been detected in waters near the Tianjin port, the State Oceanic Administration (SOA) said acknowledging that it was spreading into the waters of the port which is on the western shore of the Bohai Bay. The findings were based on monitoring reports from Sunday, according to the SOA.

Sodium cyanide is a highly toxic white, water-soluble powder that prevents the body from using oxygen.

Density below normal

The detected density of the dangerous chemical was below the normal standard and does not pose a threat to the marine environment for the time being, state-run Xinhua news agency reported.

Bao Jingling, chief engineer of Tianjin’s bureau of environmental protection, said about 700 tonnes of sodium cyanide stored at the blasts site remained mostly unaffected.

Death toll: 114

The death toll from the massive blasts last week rose to 114 after rescuers found two more bodies in the debris, Gong Jiansheng of Tianjin’s publicity department told reporters.

Identities of 54 bodies have been confirmed, he said, adding that another 70 people were still missing.

Among the bodies, 39 were fire-fighters and five were policemen. The number of missing people was previously 95, before 25 bodies were identified. Among the missing are 64 firemen, Mr. Gong said.

Rescuers have carried out four rounds of comprehensive search through what they called “a maze of containers” and search and rescue efforts are still under way.

Fraught with danger

“Navigating through the blasts zone is extremely dangerous because of the burning chemicals and twisted containers, which could collapse at any time. We had to make marks in order not to get lost,” Wang Ke, who led a group of chemical specialist soldiers, said.

Two massive blasts before midnight on August 12 wreaked havoc in areas a few kilometres away.

The blasts have affected 17,000 households and 1,700 enterprises. At least 6,000 residents have been displaced.

Combing for survivors

Soldiers are combing nearby residential quarters to search for survivors and their search has covered 6,000 households so far. As of Monday, 698 people remained in hospital, of whom 57 were in a critical condition.

More than 4,000 medical staff are treating the injured and 77 people have been discharged from hospitals.

Meanwhile, a minor explosion occurred on Monday at the blasts site hampering rescue operations.

Source: TH

#17, #2015, #august

Wild boars are gaining ground

The wild boar population in Europe is growing. However, the reasons for this growth were not yet clear. Scientists have now found that climate change plays a major role. The number of wild boars grows particularly after mild winters, suggesting that food availability is a decisive factor.

More wild boars after mild winters

Vetter and his colleagues compared annual wild boar population growth to temperature and precipitation data from twelve European countries, with data being available for up to 150 years in some regions. They identified a clear trend. “There is a sharp increase in the number of wild boars after mild winters. As mild winters are becoming more frequent, also wild boar populations are growing exponentially,” Vetter explains.

One reason is thermoregulation. If temperatures are very low, a lot of energy is necessary in order to maintain a high body temperature. As a consequence, less energy is available for reproduction and rearing the offspring in the following year. Furthermore, harsh winters claim the lives of many young animals. In warmer winters, more piglets survive.

Availability of feed makes hard winters bearable

Wild boars mainly feed on beechnuts and acorns. In so-called mast years when these trees bear a lot of fruits there is abundant feed available for the pigs. Such mast years occur in irregular intervals and, during the last decades, increasingly frequent. If a harsh winter is preceded by a mast year, the animals have enough energy for thermoregulation. The population can continue to grow despite unfavourable temperatures.

Regional differences affect wild boar populations

A wild boar population only grows in the following season if the average temperature during winter has reached a certain threshold. In southern regions this threshold is higher than in the north. “These regional differences are due to the animals’ body size. Wild boars in the south are smaller than those in the north. This changes the relation of body surface and volume and hence heat dissipation. Being small is unfavourable in the cold but thermoregulatory beneficial during hot southern summers. Regionally differing body size of wild boar is the reason why population growth began virtually simultaneously throughout Europe, despite considerable differences in winter temperatures,” Vetter explains.

Vetter and the research team at FIWI working with wild boars are going to continue their research in this field. “Wild boars produce a surprisingly large number of young animals compared to other ungulates. This enables the strong growth of populations which we are currently observing. Therefore we are particularly interested in the factors that influence reproduction of this species,” Vetter underlines.

 Source: SD

#17, #2015, #august

Greenland ice sheet’s winds driving tundra soil erosion, study finds

Strong winds blowing off the Greenland Ice Sheet are eroding soil and vegetation in the surrounding tundra, making it less productive for caribou and other grazing animals, carbon storage and nutrient cycling, a study finds.

Arctic soils are a critical but fragile ecological resource threatened by wildfire, permafrost degradation and other climate-related disturbances that are well studied. But wind-driven soil erosion has not been well documented, especially in western Greenland where it poses the greatest threat to soil stability.

The findings appear in the journal Annals of the Association of American Geographers.

“Understanding the current distribution of wind-eroded patches is a first step toward a more complete picture of regional wind erosion and its ecological impacts, especially as the Arctic continues to experience rapid environmental change and warming temperatures,” says lead author Ruth Heindel, a Ph.D. student in Dartmouth’s Department of Earth Sciences and a fellow in the IGERT Polar Environmental Change program.

The researchers used satellite imagery and remote sensing techniques to analyze wind erosion in the Kangerlussuaq region of western Greenland, where bare ground patches around the ice sheet are much less productive than the surrounding landscape. The region’s soils have developed on a layer of loess, or loose sediment that is easily eroded by the wind.

The researchers wanted to know if soil erosion is controlled by proximity to the ice sheet or by the lay of the land, including the direction and steepness of nearby hillsides. In addition, they considered whether bare patches near the ice sheet are similar in size, distribution and denudation as those farther away since wind patterns, vegetation and climate all vary with distance from the ice sheet. Winds blowing off the ice sheet tend to be drier and colder than those coming off the fjord.

Results showed that bare patches covered 22 percent of the land in the study area, ranging in size from about 100 square feet to more than 1,000 square feet. The bare patches were more widespread near the ice sheet but restricted to steep south-facing slopes farther away from the ice sheet. This pattern suggests that strong downslope winds blowing off the ice sheet are responsible for the soil erosion. In addition, the eroded patches close to the ice sheet contain less vegetation than those farther away.

The vegetation around the eroded areas is a mixture of shrubs and grasses, but grasses dominate within the eroded patches. Across the Arctic, shrub species are expanding into grass habitat, but the new findings show how wind erosion may limit the spread of shrubs by providing better habitat for grasses or an environment dominated by lichens, mosses, cyanobacteria and microfungi.

The findings are a snapshot of current soil erosion in western Greenland rather than an analysis of changes over time, which the researchers are currently conducting. The Greenland Ice Sheet has experienced record melting in recent years, but it is relatively stable in western Greenland. If the ice sheet retreats in this region, soil erosion is expected to be more restricted to steep south-facing slopes, but the already bare patches could remain denuded for a long time.

Source: SD

#17, #2015, #august

Ascent or no ascent? How hot material is stopped in Earth’s mantle

Gigantic volumes of hot material rising from the deep earth’s mantle to the base of the lithosphere have shaped the face of our planet. Provided they have a sufficient volume, they can lead to break-up of continents or cause mass extinction events in certain periods of the Earth’s history. So far it was assumed that because of their high temperatures those bodies — called mantle plumes — ascend directly from the bottom of the earth’s mantle to the lithosphere. Scientists explain possible barriers for the ascent of these mantle plumes and under which conditions the hot material can still reach the surface. In addition, the researchers resolve major conflicts surrounding present model predictions.

The largest magmatic events on Earth are caused by massive melting of ascending large volumes of hot material from Earth’s interior. The surface manifestations of these events in Earth’s history are still visible in form of the basaltic rocks of Large Igneous Provinces. The prevailing concept of mantle plumes so far was that because of their high temperatures, they have strongly positive buoyancy that causes them to ascend and uplift the overlying Earth’s surface by more than one kilometer. In addition, it was assumed that these mantle plumes are mushroom-shaped with a large bulbous head and a much thinner tail with a radius of only 100 km, acting as an ascent channel for new material. But here is the problem: In many cases, this concept does not agree with geological and geophysical observations, which report much wider zones of ascending material and much smaller surface uplift.

The solution is to incorporate observations from plate tectonics: In many places on Earth’s surface, such as in the subduction zones around the Pacific, ocean floor sinks down into Earth’s mantle. Apparently, this material descends up to a great depth in Earth’s mantle over several millions of years. This former ocean floor has a different chemical composition than the surrounding Earth’s mantle, leading to a higher density. If this material is entrained by mantle plumes, which is indicated by geochemical analyses of the rocks of Large Igneous Provinces, the buoyancy of the plume will decrease. However, this opens up the question if this hot material is still buoyant enough to rise all the way from the bottom of Earth’s mantle to the surface.

GFZ-researcher Juliane Dannberg: “Our computer simulations show that on the one hand, the temperature difference between the plume and the surrounding mantle has to be high enough to trigger the ascent of the plume. On the other hand, a minimum volume is required to cross a region in the upper mantle where the prevailing pressures and temperatures lead to minerals with a much higher density than the surrounding rocks.”

Under these conditions, mantles plumes with very low buoyancy can develop, preventing them from causing massive volcanism and environmental catastrophes, but instead making them pond inside of Earth’s mantle. However, mantle plumes that are able to ascend through the whole mantle are much wider, remain in Earth’s mantle for hundreds of millions of years and only uplift the surface by a few hundred meters, which agrees with observations.

Source: SD

#17, #2015, #august

‘Brainy’ mice raise hope of better treatments for cognitive disorders

Researchers have created unusually intelligent mice by altering a single gene and as a result the mice were also less likely to feel anxiety or recall fear.

It sheds light on the molecular underpinnings of learning and memory and could form the basis for research into new treatments for age-related cognitive decline, cognitive disorders such as Alzheimer’s disease and schizophrenia, and other conditions.

The researchers altered a gene in mice to inhibit the activity of an enzyme called phosphodiesterase-4B (PDE4B), which is present in many organs of the vertebrate body, including the brain.

In behavioural tests, the PDE4B-inhibited mice showed enhanced cognitive abilities.

They tended to learn faster, remember events longer and solve complex exercises better than ordinary mice.

For example, the “brainy mice” showed a better ability than ordinary mice to recognise another mouse that they had been introduced to the day before. They were also quicker at learning the location of a hidden escape platform in a test called the Morris water maze.

However, the PDE4B-inhibited mice also showed less recall of a fearful event after several days than ordinary mice.

The published findings are limited to mice and have not been tested in humans, but PDE4B is present in humans. The diminished memory of fear among mice with inhibited PDE4B could be of interest to researchers looking for treatments for pathological fear, typified by Post-Traumatic Stress Disorder (PTSD).

The PDE4B-inhibited mice also showed less anxiety. They spent more time in open, brightly-lit spaces than ordinary mice, which preferred dark, enclosed spaces.

Ordinary mice are naturally fearful of cats, but the PDE4B-inhibited mice showed a decreased fear response to cat urine, suggesting that one effect of inhibiting PDE4B could be an increase in risk-taking behaviour.

So, while the PDE4B-inhibited mice excelled at solving complex exercises, their low levels of anxiety could be counterproductive for a wild mouse.

Dr Steve Clapcote, Lecturer in Pharmacology in the University of Leeds’ School of Biomedical Sciences, led the study. He said: “Cognitive impairments are currently poorly treated, so I’m excited that our work using mice has identified phosphodiesterase-4B as a promising target for potential new treatments.”

The researchers are now working on developing drugs that will specifically inhibit PDE4B. These drugs will be tested in animals to see whether any would be suitable for clinical trials in humans.

Dr Alexander McGirr, a psychiatrist in training at the University of British Columbia, who co-led the study, said: “”In the future, medicines targeting PDE4B may potentially improve the lives of individuals with neurocognitive disorders and life-impairing anxiety, and they may have a time-limited role after traumatic events.”

Dr Laura Phipps of Alzheimer’s Research UK, who were not involved in the study, said:

“This study highlights a potentially important role for the PDE4B gene in learning and memory in mice, but further studies will be needed to know whether the findings could have implications for Alzheimer’s disease or other dementias. We’d need to see how this gene could influence memory and thinking in people to get a better idea of whether it could hold potential as a target to treat Alzheimer’s.

“There is currently a lack of effective treatments for dementia and understanding the effect of genes can be a key early step on the road to developing new drugs. With so many people affected by dementia, it is important that there is research into a wide array of treatment approaches to have the best chance of helping people sooner.”

Source: SD

#17, #2015, #august

Critically endangered species successfully reproduced using frozen sperm from ferret dead for 20 years

Black-footed ferrets, a critically endangered species native to North America, have renewed hope for future survival thanks to successful efforts by a coalition of conservationists, to reproduce genetically important offspring using frozen semen from a ferret who has been dead for approximately 20 years. The sire, ‘Scarface,’ as he is affectionately called, was one of the last 18 black-footed ferrets to exist in the world in the 1980s.

Initially, scientists used fresh semen to artificially inseminate females who failed to naturally mate with males, resulting in 135 kits. With just a few founders to rebuild an entire species, early managers of the black-footed ferret recovery program knew that genetic diversity would be lost.

Black-footed ferrets, a critically endangered species native to North America, have renewed hope for future survival thanks to successful efforts by a coalition of conservationists, including scientists at Lincoln Park Zoo, to reproduce genetically important offspring using frozen semen from a ferret who has been dead for approximately 20 years. The sire, “Scarface,” as he is affectionately called by the team, was one of the last 18 black-footed ferrets to exist in the world in the 1980s. Eight kits, including offspring of Scarface, were born recently, significantly increasing the gene diversity of this endangered population that a dedicated team is working to recover in the wild.

Their work published Aug. 13 in the journal Animal Conservation “Recovery of Gene Diversity Using Long-Term Cryopreserved Spermatozoa and Artificial Insemination in the Endangered Black-Footed Ferret.”

Partners working to save black-footed ferrets from extinction, and recover a healthy population back to the wild include Lincoln Park Zoo, The Smithsonian Conservation Biology Institute (SCBI), U.S. Fish and Wildlife Service, Louisville Zoological Garden, Cheyenne Mountain Zoo, Phoenix Zoo and Toronto Zoo.

“Our study is the first to provide empirical evidence that artificial insemination with long-stored spermatozoa is not only possible but also beneficial to the genetic diversity of an endangered species,” said David Wildt, lead author, senior scientist and head of the Center for Species Survival at SCBI. “What we’ve done here with the black-footed ferret is an excellent example of how sperm preservation can benefit species recovery programs.”

The U.S. Fish and Wildlife Service developed and oversee the Black-Footed Ferret Recovery Program. The Association of Zoos and Aquariums’ Species Survival Plan manages the black-footed ferret breeding program at ex situ facilities, the breeding population in which is comprised of approximately 300 animals.

“The entire species survival depends on successful captive management to ensure healthy genetics over the next 100 years and to produce individuals for the reintroduction program,” explained Black-Footed Ferret Reproduction Advisor Rachel Santymire, PhD, director of the Davee Center for Endocrinology and Epidemiology at Lincoln Park Zoo. “To balance out these demands on the breeding program, we have to ensure that each individual ferret passes its genes on to the next generation.”

Over the past several years, the team has been developing assisted reproductive technology like artificial insemination and semen cryopreservation. For this study, all of the males were managed either at SCBI or at the USFWS National Black-Footed Ferret Conservation Center. Scientists collected semen samples from adult black-footed ferrets that ranged in age from one to six years old. All females were managed at SCBI.

Initially, scientists used fresh semen to artificially inseminate females who failed to naturally mate with males, resulting in 135 kits. With just a few founders to rebuild an entire species, early managers of the black-footed ferret recovery program knew that genetic diversity would be lost. Loss of genetic variation can lead to increased sperm malformation and lower success of pregnancy over time. Researchers, led by Santymire, routinely collected and preserved black-footed ferret semen for later use as part of standard operating procedures.

SCBI developed a successful laparoscopic artificial insemination technique for black-footed ferrets. Females are induced ovulators, which mean that mating itself causes the ovary to release its eggs. SCBI researchers developed a hormone treatment that artificially causes ovulation to occur. Scientists then deposited the male’s fresh or frozen-thawed sperm directly into the female’s uterus. Animal care staff closely monitored potentially pregnant females by taking weight measurements and remote monitoring of the nest boxes via closed-circuit cameras.

During the 2008 breeding season, SCBI scientists used semen samples from four male black-footed ferrets donors that had been frozen for 10 years. Black-footed ferret Population Advisor Colleen Lynch of Riverbanks Zoo and Garden conducted population genetic analysis to select pairings of deceased sperm donors with living females based on several genetic metrics including mean kinship of the parents and inbreeding coefficients of potential offspring to maximize the genetic benefit of successful pairings. In the years that followed, subsequent AIs incorporated semen that had been cryopreserved up to 20 years, also resulting in successful pregnancies.

“Our findings show how important it is to bank sperm and other biomaterials from rare and endangered animal species over time,” said Paul Marinari, senior curator at the Smithsonian Conservation Biology Institute. “These ‘snapshots’ of biodiversity could be invaluable to future animal conservation efforts, which is why we must make every effort to collect, store and study these materials now.”

Source: SD

#17, #2015, #august

Prehistoric carnivore dubbed ‘scarface’ discovered in Zambia

Scientists have identified a new species of pre-mammal in what is now Zambia. Thanks to a unique groove on the animal’s upper jaw, it was dubbed Ichibengops, which combines the local Bemba word for scar, and the common Greek suffix for face. Put simply: Scarface.

Believed to be roughly the size of a dachshund, Ichibengops lived around 255 million years ago.
 Scientists at The Field Museum have identified a new species of pre-mammal in what is now Zambia. Thanks to a unique groove on the animal’s upper jaw, it was dubbed Ichibengops (Itchy-BEN-gops), which combines the local Bemba word for scar (ichibenga), and the common Greek suffix for face (ops). Put simply: Scarface.

Believed to be roughly the size of a dachshund, Ichibengops lived around 255 million years ago, and was a member of Therocephalia, a group of ancient mammal relatives that survived the largest mass extinction in history (the Permian-Triassic extinction). The species description was published in the Journal of Vertebrate Paleontology by University of Utah, University of Washington and Burke Museum, and The Field Museum.

“Discoveries of new species of animals like Ichibengops are particularly exciting because they help us to better understand the group of animals that gave rise to mammals,” said Field Museum’s Kenneth Angielczyk, PhD, associate curator of paleomammalogy. “One interesting feature about this species in particular is the presence of grooves above its teeth, which may have been used to transmit venom.”

Indeed, venomousness is rare among mammals and their extinct relatives. Only a handful of modern mammals produce venom, including the platypus and certain species of shrews. One other extinct therocephalian, Euchambersia, has been suggested to be venomous, but even among ancient mammal relatives this is an exception rather than the rule. Although the trait is uncommon, it may have proved advantageous to carnivores by enabling them to better capture prey and defend themselves.

Angielczyk, whose work focuses on ancient mammal relatives, explained the importance of finding new species like Ichibengops. “By studying the effects of the Permian-Triassic mass extinction and the subsequent recovery, we can apply the lessons we learn to the mass extinction being caused by humans today.”

Source: SD

#17, #2015, #august

Heat release from stagnant deep sea helped end last Ice Age

The build-up and subsequent release of warm, stagnant water from the deep Arctic Ocean and Nordic Seas played a role in ending the last Ice Age within the Arctic region, according to new research.

The build-up and subsequent release of warm, stagnant water from the deep Arctic Ocean and Nordic Seas played a role in ending the last Ice Age within the Arctic region, according to new research led by a UCL scientist.

The study, published today in Science, examined how the circulation of the ocean north of Iceland — the combined Arctic Ocean and Nordic Seas, called the Arctic Mediterranean — changed since the end of the last Ice Age (~20,000-30,000 years ago).

Today, the ocean is cooled by the atmosphere during winter, producing large volumes of dense water that sink and flush through the deep Arctic Mediterranean. However, in contrast to the vigorous circulation of today, the research found that during the last Ice Age, the deep Arctic Mediterranean became like a giant stagnant pond, with deep waters not being replenished for up to 10,000 years.

This is thought to have been caused by the thick and extensive layer of sea ice and fresh water that covered much of the Arctic Mediterranean during the Ice Age, preventing the atmosphere from cooling and densifying the underlying ocean.

Dr David Thornalley (UCL Geography) said: “As well as being stagnant, these deep waters were also warm. Sitting around at the bottom of the ocean, they slowly accumulated geothermal heat from the seafloor, until a critical point was reached when the ocean became unstable.

“Suddenly, the heat previously stored in the deep Arctic Mediterranean was released to the upper ocean. The timing of this event coincides with the occurrence of evidence for a massive release of meltwater into the Nordic Seas. We hypothesize that this input of melt water was caused by the release of deep ocean heat, which melted icebergs, sea-ice and surrounding marine-terminating ice sheets.”

This study highlights the important impact that changes in ocean circulation can have on climate, due to the ocean’s capacity to redistribute vast quantities of heat around the globe. For example, scientists are currently concerned that ongoing changes in ocean circulation may result in warmer subsurface water that will cause enhanced melting and retreat of certain ice sheets in Greenland and Antarctica.

Dr Thornalley added: “To help predict the role of the ocean in future climate change, it is useful to investigate how ocean circulation changed in the past and what the associated climate effects were.”

In this study, researchers from UCL, Woods Hole Oceanographic Institute and other partner institutions analysed the composition of calcite shells of small single-celled organisms (called foraminifera) that are found in ocean floor sediment. The shells of these organisms record the chemistry of the deep ocean at the time they were living, enabling the researchers to reconstruct past changes in ocean circulation.

By measuring the radiocarbon content of these shells, the research team was able to determine how rapidly deep water was being formed in the Arctic Mediterranean. A number of different techniques were then used to constrain past temperature changes, including measuring the ratio of magnesium and calcium, and the arrangement of isotopes of carbon and oxygen within the calcite shells of the foraminifera, both of which vary according to the temperature of the water in which the foraminifera grew.

A warmer, deep Arctic Mediterranean during glacial times has been suggested in previous studies, too. As summarised by co-author Dr Henning Bauch (GEOMAR/Germany) “It is good to see that new, independent proxy data would give strong support now to these former hypotheses.”

Source: SD

#17, #2015, #august